No RSL through Spartan board

Today is Bag Day! So far we have not been able to get our RSL to light. We are using a Spartan board, but it only passes the RSL signals through it, no modification.

We have swapped out multiple RSLs. We measured voltage at the RSL socket, but saw none. We measured voltage at the pis on the Spartan board, and again saw none.
We are now looking for suggestions.

BTW, our RoboRio is mounted in such a way that it is very difficult to gain access to. We know this is not a great idea, but it is what it is. We are making no excuses for it.

Super weird. We have a Spartan board and our RSL is working perfectly.

Did you try measuring at the RoboRio’s port?

Did you wire the RSL correctly? Mainly the jumper wire between La and Lb terminals.

If there isn’t any voltage at the board level this doesn’t matter for troubleshooting.

Yep, that was the first thing I checked.


There is in lies the rub. Gaining access to the RoboRio its self is a nightmare, but, that may be all we do this afternoon/evening.

Does the RSL LED on the roborio blink? Can you see the RSL LED?

Why aren’t you using the RSL output of the RoboRio?

The Spartan Board directly passes it through to Molex connector. See photo below:

That is the first thing I will be looking into this afternoon.

The Spartan Board interfaces and passes the RSL signal, unmodified, through the board. It is one of the approved “Active Device” MXP expansion boards.

Does the RSL on the RoboRio illuminate properly?




Stick a volt meter on the pair of wires. You should see a voltage. If you do, the problem is on the light side. If you don’t, it’s a roboRIO side/wiring problem.

The spartan board has 2 traces connecting it through. They don’t even connect into the main ground plane. The only thing that possibly comes to mind that could be wrong on the spartan board side is maybe a connector didn’t get soldered perfectly?

Good luck!

What color is the power LED on the roboRIO?

I’ll let you know once I have had a chance to inspect it this evening.


After verifying the RSL Status LED on the RoboRio was lit solid yellow, we re-soldered the pins coming through the SB. We the measured the voltage on the pins and found it still at 0 vdc. We then gently separated the SB from the RoboRio enough to inspect the socket on the back side of the SB. That is when we found the root cause.

When we assembled the SSB to the RoboRio, we either misaligned the socket to the pins, or the socket was bent slightly to the side when delivered. Either way, a straightending of the socket restored the connection and the RSL/BFL started working.

No, this picture is NOT upsidedown, that is how it is mounted, and how tightly packet the Hummingbird is.

Happy to hear you fixed it Bill!